ABSTRACT
Proterozoic magmatism (2.5 ± 0.1 to 1.0 ± 0.1 Ga ago) represents a very important transition from the magmatism of the early stages of the Earth’s evolution to the Phanerozoic magmatism that continues to the present day. The type of tectonomagmatic activity in all the Precambrian shields allows the Proterozoic to be clearly divided into two radically different stages: from 2.5 to 2.2–2.0 Ga ago, and from 2.0 to 1.0 Ga ago, differing both in their type of magmatic processes and in their geodynamics. The Baltic Shield is the largest Precambrian basement inlier of the Russian Platform. According to Kratz et al., it is divided into four geoblocks of differing ages: the Caledonian, Dahlsland, Svecofennian and Kola–Karelian. The volcanic and intrusive rocks of the eastern Baltic Shield are related to the so-called Karelides, emplaced during the Karelian, or Sumian–Sariolian, tectonomagmatic cycle.
